1. Technical Field
This disclosure pertains to wireless communication and more particularly to devices that perform connectionless communications, and, in particular, low energy Bluetooth (BLE) devices and methods.
2. Background
The Bluetooth Specification includes both connected and connectionless sessions. Connectionless sessions may be referred to in the art as advertising or broadcasting sessions. As detailed in the Bluetooth Specification, security and authentication elements are employed only in a connected session between two BLE devices. There are no security elements during connectionless sessions. An example of a Bluetooth system is illustrated in FIG. 1. This example shows Bluetooth devices, 102, 104, 106 and 108. Devices 102 and 108 are shown communicating in a connected process, as illustrated by arrows 111 and 112, while Bluetooth devices 102 and 104 are communicating in a connectionless process, as illustrated by arrow 115. Device 102 is broadcasting an advertising message. No security is available for this message. Likewise, No security is available for an advertising communication between BLE device 102 and BLE device 106 as shown by line 116. “No security” in this context means at least that it is not possible to determine what device is sending the message or whether the message has been corrupted. Device 106 may also be advertising, with no security available. Thus, device 104 cannot tell which advertisement is coming from which BLE device. At the time of this disclosure, security is available in BLE only while using the connected profile, which security is typically provided using a hardware authentication chip. Further, there are disadvantages in that it is necessary to define the master and slave, and utilize two-way traffic that is limiting from power consumption, latency and use case aspects.
There are instances in which frequent and significant use is made of connectionless sessions, such as Contiguity Profile where it is used for discovery and proximity measurements. Authentication is desirable in such instances, as often there are many BLE devices advertising or broadcasting within BLE range, and errors and security vulnerabilities can occur if one BLE advertisement or broadcast is mistaken for another. Therefore, it would be highly desirable if an apparatus and process were available that allowed connectionless authentication of BLE advertisements, broadcasts, and devices.